1. Technical Field
The invention relates to racks for loading billboards or bulletin boards, particular to racks capable of adjusting height of such boards.
2. Related Art
Usually, those large boards such as black boards or white boards used in classroom or exhibition are fastened on a wall because of cumbersomeness. If those boards placed in a classroom or exhibition cannot be adjusted in height, the information on the boards will not be clearly seen by the audience. Further, the weight of those large boards may exceed 100 kg, the supports of them must be difficult in structure.